Semester

Summer

Date of Graduation

2002

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Robert A. Dailey.

Abstract

Bacterial infections associated with mastitis reduce pregnancies in cattle. Effects on pregnancy and incidence of mastitis in sheep were investigated after immunization with peptidoglycan-polysaccharide (PG-PS) and killed cells from Strep. pyogenes. Rambouillet (n = 100) and mixed breed (n = 18) ewe lambs were immunized (∼d42 and 22 before breeding) with PG-PS (30mugPG/kg/bw) or killed cells or were not immunized (Control, n = 117). IgG antibodies were detected by ELISA. Ewes were bred at synchronized estrus. All immunized and half of non-immunized ewes were challenged with PG-PS (60mugPG/kg/bw) d5 after breeding. Although proportion of ewes pregnant at d42 did not differ, probability of pregnancy decreased with total dose of PG-PS (p < .05). Incidence of mastitis in mixed breed ewes in the middle and at the end of lactation did not differ. In conclusion, immunization of ewe lambs with PG-PS or killed cells of Strep. pyogenes did not improve pregnancy rate or incidence of mastitis after PG-PS challenge.

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